(a) Technical Field
The present disclosure is related to a display device, and more particularly, to a liquid crystal display of a vertical alignment (VA) mode.
(b) Description of the Related Art
A display device, such as a liquid crystal display (LCD), an organic light emitting diode (OLED) display, or the like, generally includes a display panel including a plurality of pixels for displaying an image.
The display panel of a liquid crystal display includes a liquid crystal layer including liquid crystal molecules, an electric field generating electrode for controlling alignment of the liquid crystal molecules in the liquid crystal layer, a plurality of signal lines for applying a voltage to at least some of the electric field generating electrodes, and a plurality of switching elements connected thereto. When a voltage is applied to the electric field generating electrode, an electric field is generated in the liquid crystal layer, thereby realigning the liquid crystal molecules. Accordingly, an image may be displayed by adjusting an amount of transmitted light. The display panel may include at least one polarizer to control an amount of transmitted light.
The electric field generating electrode included in the liquid crystal display includes a pixel electrode for receiving a data voltage and an opposed electrode for receiving a common voltage. The pixel electrode may receive a data voltage through the switching element, which may be formed of, e.g., a thin film transistor. The pixel electrode and the opposed electrode may be configured to face each other with the liquid crystal layer interposed therebetween, or may be disposed on the same side with respect to the liquid crystal layer.
Each pixel may display a primary color, such as red, green, blue, or the like.
Among liquid crystal displays, there is a vertical alignment (VA) mode in which liquid crystal molecules are arranged such that major axes thereof are aligned mainly vertically with respect to a surface of the display panel when an electric field is not applied to the liquid crystal layer. A liquid crystal display implementing the vertical alignment (VA) mode generally has a high contrast ratio and a wide standard view angle in comparison with other liquid crystal displays.
To achieve a wide view angle in a liquid crystal display implementing the vertically aligned mode, a plurality of subregions or domains having different alignment directions of liquid crystal molecules may be formed in one pixel. An example of a method for forming a plurality of domains may include forming a cutout, such as a slit, in the electric field generating electrode. In the case in which a cutout is formed in the electric field generating electrode, a fringe field is formed by an edge of the cutout, which realigns the liquid crystal molecules. Accordingly, a plurality of domains may be formed.
The liquid crystal molecules in each domain or subregion are tilted mainly in the same direction.
An initial alignment method is used for hastening a response speed and implementing a wide viewing angle. The initial alignment method provides a pretilt to the liquid crystal when an electric field is not applied to a liquid crystal layer. In order to provide pretilts having various predetermined directions to the liquid crystal molecules, an alignment layer having various alignment directions may be employed, or an alignment aid may be added to a liquid crystal layer or an alignment layer and cured after applying an electric field to the liquid crystal layer.
However, to manufacture a liquid crystal display including an alignment aid for a pretilt, an additional process line for an alignment aid, an ultraviolet ray curing process, and the like are often required, which would lead to extra cost. Therefore, problems of increasing manufacturing cost of a liquid crystal display, requiring additional manufacturing equipment, and complicating a manufacturing process exist. The above information disclosed in this Background section is only for enhancement of understanding of the background of the present disclosure and therefore may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.